A time series forecasting project comparing SARIMA and Holt-Winters models to analyze temperature trends in Kenya using real-world climate data.
# Kenya Temperature Forecasting - SARIMA & Holt-Winters
## Overview
This project presents a time series analysis of Kenya's monthly average temperature from 1991 to 2016. The objective is to model and forecast temperature for a 12-month horizon using classical statistical methods.
Two models are implemented and compared:
- Seasonal ARIMA (SARIMA)
- Holt-Winters Exponential Smoothing
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## Dataset
| Attribute | Detail |
|-----------|--------|
| Source | Open Africa Datasets |
| Variable | Monthly Average Temperature (°C) |
| Period | January 1991 – December 2016 |
| Frequency | Monthly |
| Observations | 312 |
| Missing Values | None |
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## Methodology
### 1. Exploratory Data Analysis
* The series exhibits clear annual seasonality (12-month cycle) with a mild upward warming trend.
* Additive seasonal decomposition confirms a stable seasonal amplitude of approximately ±1.5°C and largely random residuals, justifying the use of an additive modelling framework.
### 2. Stationarity & Preprocessing
* The Augmented Dickey-Fuller (ADF) test returned a p-value of 0.3658, confirming the series is non-stationary.
* First-order differencing (d = 1) was applied, after which the series became stationary and mean-reverting with no visible trend.
### 3. Model Development
**SARIMA(3,1,1)(2,0,1)[12]**
Selected via stepwise Auto ARIMA (AIC minimisation, AIC = 396.85), consistent with ACF/PACF analysis of the differenced series.
| Component | Terms |
|-----------|-------|
| Non-seasonal | AR(3), I(1), MA(1) |
| Seasonal | SAR(2), SMA(1), m = 12 |
> Note: No seasonal differencing (D = 0) was applied. The seasonal structure is captured parametrically through the SAR and SMA terms, with the
> SAR(L12) coefficient of 1.094 implying near-implicit seasonal differencing within the AR structure.
**Holt-Winters Exponential Smoothing**
* Included as an interpretable benchmark against the SARIMA model.
* Fitted with additive trend and additive seasonality (period = 12), appropriate …